Depends on what heatsink/fan solution you've mounted on the processor, the
speed the processor fan speed is turning, and naturally the room temp and
case. I have a 640 3.2 GHz Prescott w/ stock heatsink/fan on a Intel 955XBK
motherboard in a Lian Li 1100 plus case. I've adjusted my processor fan
speed to where the processor temps run @ 40-44C small load, and 48-53C full
load. The maximum DO NOT exceed temperature for the 3.2 GHz 640 is 67C. If
your coming close to 67C you need a better case.